[ALSA] Fix possible races in timer callbacks

Fix possible races in timer callbacks.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/sound/core/timer.c b/sound/core/timer.c
index 74637cef6d2c..6aad411dd7b8 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -662,12 +662,13 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
         struct snd_timer_instance *ti, *ts;
         unsigned long resolution, ticks;
         struct list_head *p, *q, *n, *ack_list_head;
+        unsigned long flags;
         int use_tasklet = 0;
 
         if (timer == NULL)
                 return;
 
-        spin_lock(&timer->lock);
+        spin_lock_irqsave(&timer->lock, flags);
 
         /* remember the current resolution */
         if (timer->hw.c_resolution)
@@ -752,7 +753,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
 
         /* do we have any slow callbacks? */
         use_tasklet = !list_empty(&timer->sack_list_head);
-        spin_unlock(&timer->lock);
+        spin_unlock_irqrestore(&timer->lock, flags);
 
         if (use_tasklet)
                 tasklet_hi_schedule(&timer->task_queue);